陨石分类研究进展及其地学意义

DEVELOPMENT OF STUDIES ON METEORITE TAXOLOGY AND ITS SIGNIFICANCE IN EARTH SCIENCE

近 40年来陨石分类学经历了 3个发展阶段 :6 0～ 70年代 ,由根据陨石的矿物结构的分类方法发展为球粒陨石的化学—岩石学分类法和铁陨石的化学群分类法 ;70～ 80年代 ,提出了分异型陨石和未分异型陨石的概念。球粒陨石被认为是未分异型陨石 ,而其它陨石 (铁陨石、石铁陨石和无球粒陨石 )大多被划入分异型陨石 ;80～ 90年代以来 ,陨石氧同位素组成成为了陨石成因分类的一个主要依据 ,使陨石分类学进入了一个新的成因分类阶段。作者对 80～ 90年代以来新确立的 R群、K小群、CR群和 CK群球粒陨石 ,以及根据氧同位素划分出的原始型无球粒陨石系列 :A-L无球粒陨石、Winonaites无球粒陨石和 Brachinites无球粒陨石进行了介绍。笔者对陨石研究和陨石分类学的发展在估算地球整体成分 ,探讨地球成因和早期演化历史方面的重要意义进行了说明 。

In recent 40 years, meteorite taxology has undergone three development stages. In the 1960-1970s, chemical-petrologic classification of chondrites and chemical classification of iron meteorite were established. In the 1970-1980s, achondrites, stony irons and irons were considered to be from differentiated meteorite bodies. In the 1980-1990s, the oxygen isotopic compositions of meteorites were taken as an important foundation for meteorite classification, so meteorite taxology entered a new original classification stage. In this paper, R chondrite, K chondrite, CR chondrite and CK chondrite are reported to be new chemical groups distinguished in recent 20 years, and A-L achondrite, Winonaite achondrite and Brachinite achondrite, to be primitive achondrites based on the oxygen isotopic compositions. Finally, significance of meteorite classification in earth science is discussed, calling earth scientists to pay attention to the developments on meteoritics and meteorite taxology.